1. Field of the Disclosure
This disclosure relates in general to flow calibration check of several liquid flow streams and its use in multi-port printing devices.
2. Description of the Related Art
Printing liquid materials to form layers in electronic devices requires careful control of the liquid flow rates. When applied to a multi-port printer even small variations in liquid flow rates may cause performance problems with the resulting electronic device. Calibration of the multi-port printer, while necessary, can be time consuming and reduce throughput in a manufacturing operation. To achieve consistent performance existing calibration methods include use of a mass balance to collect liquid over a defined time period to obtain the mass flow rate, and repeating this procedure at selected intervals to ensure the mass flow rate is not varying with time. This mass balance method must be repeated for each port of the multi-port printer, and can require 20 to 30 minutes per port.
Another calibration method involves the production of complete electronic devices, followed by testing the completed electronic device for functionality and uniform operation. In the instance where the electronic device is an Organic Light Emitting Diode (OLED), uniform luminance of the OLED can provide evidence of uniformity of the flow rates in the multi-port printer used to produce the OLED. This production and testing of complete electronic devices may involve a considerable amount of time.
In yet another calibration method, each port of the multi-port printer can be calibrated individually using a known steady-state flow through a flow meter using at least three distinct flow rates to establish a flow rate curve for each port. Again, the time required may exceed 20 minutes per port.
While the calibration step is important and must be conducted to ensure proper control over multi-port printing processes, when to timely conduct the calibration steps is decided in a variety of approaches. There is a continuing need for a simpler and faster method to determine when the calibration is required for multi-port printers.